[BUG] Corrupted Chat

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

on typing anything into window:

 API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.19.content.11: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These
     blocks must remain as they were in the original response."},"request_id":"req_011CZqDHdNM4ZudjGxnucpZd"

and while trying to compact:

Error: Error during compaction: API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.19.content.11: thinking or redacted_thinking blocks in the latest assistant message
     cannot be modified. These blocks must remain as they were in the original response."},"request_id":"req_011CZqFKdpvKyoYz2MvmwbFV"}

only solution was to clear / exit.

What Should Happen?

Respond normally.

Error Messages/Logs

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.19.content.11: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These
     blocks must remain as they were in the original response."},"request_id":"req_011CZqDHdNM4ZudjGxnucpZd"



Error: Error during compaction: API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.19.content.11: thinking or redacted_thinking blocks in the latest assistant message
     cannot be modified. These blocks must remain as they were in the original response."},"request_id":"req_011CZqFKdpvKyoYz2MvmwbFV"}

Steps to Reproduce

Unsure. I had a long chat spanning days. Token usage was 480k.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.94

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Xterm

Additional Information

_No response_